Electrophotographic processes for forming images upon media are well known in the art. Typically, these processes include an initial step of charging a photoreceptor which may be provided in the form of a drum or continuous belt having photoconductive material. Thereafter, an electrostatic latent image may be produced by exposing the charged area of the photoreceptor to a light image using a light-emitting diode array, or scanning the charged area with a laser beam in exemplary configurations.
Particles of toner may be applied to the photoreceptor upon which the electrostatic latent image is disposed such that the toner particles are transferred to the electrostatic latent image. Thereafter, a transfer step occurs wherein the toner particles are transferred from the photoreceptor to the media while maintaining the shape of the image formed upon the photoreceptor. A fusing step is utilized to fix the toner particles in the shape of the media. A subsequent step can include cleaning or restoring the photoreceptor for a next printing cycle.
Two operational parameters greatly affect the final print quality of the toner image supplied to the media. For example, the electric field in the transfer nip of an electrophotographic printing device and an effective temperature in the fuser nip are vital to ensure optimized image quality and achievable print. Two variables in printing media that affect the electric fields in the transfer nip and the effective temperature in the fuser nip are basis weight and water content. These two variables manifest themselves as differences in dielectric thickness, heat capacity and thermal conductivity for a given media in an environment.
Referring to toner transfer operations, toner transfer electric fields are largely dependent upon the capacitance of the media. Most transfer systems of conventional electrophotographic devices use constant supply voltages that are applied to respective conductive transfer rollers. Typically, the applied voltages are set relatively high to accommodate thicker (i.e., lower capacitance) media. Unfortunately, this condition can result in less than optimum electric fields for thinner (i.e., higher capacitance) media. In some conventional arrangements, a user can manually adjust fuser temperatures using a control panel or software. Typically, such adjustments are made after problems in fusing quality are noticed.
The above conventional image forming system configurations have associated drawbacks of requiring knowledge of the user to implement transfer and fusing adjustments as well as knowledge of the proper adjustment to improve transfer and fusing quality. Therefore, a need exists to provide image forming devices and methods which provide improved print quality for different types of media.